Electric machine



March 7, 1945. v. w. SHERMAN ETAL 2,372,453

ELECTRIC MACHINE 2 Sheets-Sheet 1 INVENT Rs VERNON Hf 5H5 N IIIID EUGENE GONYOU ATTORNEY6- Qriginal Filed March 2, 1942 March 27, 1945. H RMAQ ET L 2,372,453

ELECTRIC MACHINE Original Filed March 2, 1942 2 Sheets -Sheet 2 Bymvn UG-ENE GOA/70 U ATTORNE6.

Patented Mar. 27, 1945 ELECTRIC MACHINE Vernon W. Sherman, Summit, N. J., and Eugene Gonyou, Detroit, Mich, assignors to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Continuation of application Serial No. 432,938, March 2, 1942. This application March 31, 1944,

Serial No. 528,920

18 Claims.

This invention relates to alternating current,

dynamo-electric machines.

The need for a high output dynamo-electric machine for installation on mobile units, such as aircraft, has long existed. Efiorts toprovide a satisfactory machine have not been entirely successful, mainly because of the excessive weight. In many constructions heretofore known, it has been satisfactory to mount a dyname-electric machine from both ends or along the sides by means of a surrounding casing. Thus no real problem was encountered as to support, but the limitations as toweight and space imposed by aircraft reqirements make necessary or desirable the supporting from one end. 1 a

In the present instance, a design and construction has been evolved in which the electrical losses have been reduced, the cooling has been improved and the mechanical construction of the generator has been materially simplified.

It is accordingly the general'objectof this invention to provide an improved dynamo-electric machine having the aforesaid characteristics.

Another object is to provide a dynamo-electric machine that may conveniently be supported from one 'end.

A further object is to improve the association of laminations, bars, and end rings of a dynamoelectric machine so that supporting of the ma- Other objects and advantages will be appar went from the following description which with the accompanying drawings, constitutes a disclosure of a preferred form of our invention.

In the drawings where reference numerals are used to designate corresponding parts referred to in the description,

Fig. 1 is a longitudinal sectional view of the generator;

Fig. 2 is a sectional view along line'2-2 of Fig. 1 looking in the direction indicatedby the arrows;

Fig. 3 vis a sectional view along line 3-8 of Fig. 1 looking in the direction of the arrows;

Fig. 4 is a detail of the cooling air impeller;

Fig. 5 is a detail of one end of the machine;

Fig. 6.1:; an end elevation of the generator from the right side of Fig. 1;

Fig. 7 is a sectional view on line 1-1 of Fig. 1, some parts being shown in elevation for clearness;

Fig. 8 is a detail of one end with some of the parts removed; and

Fig. 9 is an enlarged sectional view of the parts within the circle 9 in Fig. 1.

The stator assembly of the machine comprises laminations III which are assembled into a stack inaccordance with usual practice. The stack carries a winding II and is retained in assembled relation by end rings l2, l3 and T-bars H. The endring I2 has a portion l2 abutting the laminations HI and a flange l2 displaced from the portion I! in a longitudinal direction with respect to the stack of laminations l0 and extending radially outwardly farther than the portion II. The end ring l3 has a portion I3- abutting the laminations l0 and another-portion l3 displaced from the portion l3 in a longitudinal direction and extending radially outwardly farther than the portion ll;

As can be clearly seen from Figs; 3 and 5, the bars 14 are of T-shape cross-section, and slots ii are provided at spaced intervals in the stack for accommodating the base portions thereof. The upright portions of the T-bars thus extend radially from the outer periphery of the stack. Besides providing maximum strength for their cross section, the T-bars perform another important function which will be referred to later.

The T-bars i4 are welded to the portions l2 and l3 of the end rings l2 and 13 (Figs. 5 and 9). Thus the laminations III are rigidly held against both longitudinal and circumferential displacement. The ends of the T-bars l4 expand upon the heating incident to the welding and contract upon cooling after welding. This contraction causes the laminations l0 to be gripped very tightly between end rings H, and so the laminations, bars, and end rings are better enabled to constitute their own supporting struc-- ture as will be more fully explained. The flange li of the end ring [2 abuts a mating flange ll of a main support member I8. The latter is provided with bolt holes 18 and a flange 20 to facilitate securement'of the machine to an engine housingor other support. Ventilating holes Ii are also provided as illustrated.

The end ring I! is fastened to the main support member ID by means of a clamping ring 22 which consists of two halves adapted to be secured together by cap screws 23 as.shown in Fig. 2. Theringflisofchannel shape asshown 2 estates in Fig. -1, and fits tightly over the flanges 52*,

ll when the screws 23 are tightened.

The right hand end of the generator is pro vided with an end bell in which is fastened to the portion l3 oi the and ring it by cap screws 2-5. The and ring 33 is provided between the portions it and 93* with an elongated cylindrical portion provided with spaced openings The space between the annular portion of the ring 53- and the bell 2G accommodates the ends of the windings and provides space for the brushes 2? and the loads 28. The holes 26 permit ventilation and accommodate the end turns of the the stack and end rings at spaced points adiago ficienoy due to welding at this region is avoided.

cent the hub as illustrated. The end rings hi, it are provided with spaced ventilating openings 36 and have substantially similar cylindrical extensions, designated 35 and 33 respectively, which form mounting hubs for the rotor structure.

The hub portion 35 is longer than 3% for ac-- commodating the slip rings 371. An anti-friction bearing 38 mounts the end portion thereof in the end bell 26;a retaining ring 23?] securing the same against-displacement. A similar-bearing d9 mounts the hub portion 35 in the main support member 58, a split ring ill retaining the maring in place.-

The hub portion 35 is iny spllned for receiving the splined end 52 oi a drive shaft 33 which is splined at its other end at dd for con-.- nection to a driving means. v

The end bell it carries a boss 55 which is fastoned to the bell by cap screws it. Thebos is preferably split, as illustrated in Figs. 7 and 8,

the lower half or being removable to iacilitate servicing. A screwthreaded connector 38 is suitably secured in the boss to and is adapted to The rotor also carries an air impeller 59 illus-v trated in Fig. 4. This impeller has spiral blades 50 and is identical in length with the rotor stack such that it abuts the end rings 31,- 32 as shown end ring 32 and out through the openings 21. housing 5| to provide an extremely eficient coolin Fig. 1. This impeller cooperates with an outer ing means.

A housing 51 is provided, which is preferably of aluminum and is of thin ection for lightness.

At one end it is provided with an opening for the connector 18 and an air inlet mouth 52, and

the other end is formed-with a plurality of spaced j tongues 53 which abut the clamp ring 22, the

spaces 54 between the ton uesproviding air outlet openings.

It is to be notedthat the stator assembly coin-.

prising laminations 10, end rings l2 and mend bars M, are supported entirely from one end, independently of .thecasing-5i, upon the main support member I8. The stator assembly, in effect, provides its own. supporting structure or frame, and the tight and rigid association of these parts due to the contraction of the ends of the bars l4 after theneeungiaeident to the welding of the bars to the end rings :2. and it contributes to this arrangement; The end bell 24 i supported upon the end g .13, which is in turn supported through the laminations M, the bars I; and the end ring l2 upon the main support member It. The right-hand hub 35 of, the

55 continually stripped away. flows outwardly through the openings and into rotor and the splined end of the drive shaft 53 are carried through the bearing 38 upon the end bell 2B. The casing 5i rests upon the bars iii and upon the portion it of the end ring it and 5 the end bell 253. It provides no support and so can be thin and light in weight. All parts are carried through the main support member is through the stator assembly.

As previously stated and as shown in Figs. 3

lo and 5, the bars ill are of T-shape in cross section. The cross or wide portion of the T fits in the slot it in the laminations and so contributes "to the rigidity of the stator assembly, making it possible for the stator assembly to iii provide support for itself and for the parts at the right-hand end of the machine. The wide portions of the T-bars it make possible rigidity of assembly without welding of the bar to the laminations it. This reduction of electrical ef- 25 0? air.

As previously stated, the flange li of ring 12 and portions i3 of ring i3 extend radially outwardly farther than, respectively, portions H2 and it Portions l3 extend radially outwardly 39 as far a the T-bars i i extend so that the casingtil is supported on the T-bars id and the nortions l3". The flange li extends radally outwardli so that the clampi g ring 22 may engage it and may in turn extend radially outwardly about a far as the casing 5!. As is evident from Fig. l, the casing 5i abuts the clamping ring 22.

The machine is intended to be operated at speeds oirotation in the order of 5,000 B. and annular dished ring members are secured {ill to the rotor stack 29 by screws 56 for retaining the windings in place and to facilitate smooth air flow through the rotor.

The direction of the spiral of the air impeller blades 50 is such that rotation of the rotor assists 45 air to flow through the interior of the rotor.

Cooling air under pressure enters through the mouth 52 where it flows in two directions. One stream or air passes through the openings 36 at the inlet and thence out the openings 34 in the This stream of air is forcedby the shape of the impeller 49 to flow in close proximity to the under surface of the rotor iron where by virtue of its high velocity the heated layer or surface air is The other stream the spaces 5? between the stator stack and the housing 5i, thence out through the openings 54. This latter stream of .air is thus confined closely co. to the outer surface of the stack of laminations N, where its liigh velocity can most efiectively strip away the surface layer of heated'air. The

use of a relatively shallow layer of high velocity air has been found to be essential to the realization of least weight per kilowatt. For maximum generator capacity, high velocity air is ob-. tained from either an rnal blower or from a 2" ID tube whose intake end is exposed in the frontal ,area of an airplane. A pressure of 7 10" of water and a quantity c1100 cubic feet per minute are representative values. Without such a supply of air from an external source, the generator capacity is-o! course reduced, but even under these conditions (with the mouth 52 .76 open tothe atmosphere) the impeller 49 induces a relatively high velocity flow through the machine and cooling is improved thereby.

Although but one embodiment oi the inventiontions adapted to mount bearing races; said stackhaving a central axial bore; an air impeller disthe end rings to provide air passages extending longitudinally of the stator.

7. A dynamo-electric machine including a stack of laminations having a plurality of spaced peripheral grooves extending longitudinally of the stack, a pair of end rings abutting opposite ends of the stack of laminations, a casing surrounding the stack of laminations in spaced relation thereposed in said bore and secured to said end rings,

and ventilating openings in the annular portions of said end'rings.

2, In a dynamo-electric machine, a stator structure comprising a stack of laminations and a pair of end rings rigi secured together; a rotor, mounted in said sta r structure; a mounting flange having means for securement to a support; a shouldered flange on said mounting flange; a flange on one of said end rings adapted to abut said shouldered flange; a channel-shaped ring adapted to receive both of said flanges, and means for tightening said ring thereby to detachably secure said stator to said mounting flange.

- 3. A dynamo-electric machine comprising a stator structure formed of a stack of laminations and a pair of end rings positioned at opposite ends of the stack of laminations, one of the end rings having a flange; a rotor mounted in the stator structure; a support having a flange; and means detachably securing the stator structure to the support and including a channel-shaped ring receiving the flange on the one end ring and the flange on the support.

4. A dynamo-electric machine including a stack of laminations having a plurality of spaced peripheral grooves extending longitudinally of the stack, a pair of end rings abutting opposite ends of the stack of the laminations, bars disposed in the slots in the stack oflaminations, means rigidly securing the ends of the bars to the endrings, a casing enclosing the stack of laminations, and means connected with one end ring and supporting the stack of laminations through the bars and the end rings entirely independently of the casing.

5. A dynamo-electric machine including a stack of laminations, a pair of end rings abutting opposite ends of the stack, a plurality of bars extending longitudinally of the stack of laminations at the periphery thereof, means rigidly securing the ends of the bars to the rings, a casing surrounding the; stack of laminations, and means connected with one end ring and supporting the stack of laminations through the bars and the end.

rings entirely independently of the casing.

to, bars joined by their ends to the end rings and having wide portions and narrow portions, the wide portions being disposed in the slots in the stack of laminations so as to serve with the end rings to support the stack independently of the casing, and the narrow portions projecting from the stack of laminations into contact with the casing so as to maintain the spaced relation between the casing and the stack of laminations and providing a maximum of spacing between bars for circulation of cooling air between the casing and the laminations.

8. A stator assembly comprising a stack of laminations, a pair of end rings abutting opposite ends of the stack, a plurality of bars extending longitudinally of the stack of laminations at the periphery thereof, means rigidlysecuring the ends of the bars to the rings, and a supporting means connected with one end ring for enabling the stator assembly to be supported through the bars and the end rings entirely at the end of the stator assembly where the one end ring is located.

'9. A stator assembly comprising a stack of laminations, a pair of end rings abutting opposite ends of the stack, a plurality of bars extending longitudinally of the stack'of laminations at the periphery thereof, means rigidly securing the ends of the bars to the rings, a casing surrounding the stack of laminations, and a supporting means connected with one end ring for 40 enabling the stator assembly to be supported through the bars and the end rings entirely independently of the casing entirely at the end of the stator assembly where the one end ring is located.

10. A stator assembly comprising a stack of 1arninations, a pair of end rings abutting opposite ends of the stack, a plurality of bars extending longitudinally of the stack of laminations at th. periphery thereof without being .metallically bonded to the laminations, means rigidly securing the ends of the bars to the rings by metallic bonds, and a supporting means connected with one end ring for enabling the stator assembly to be supported through the bars and the end rings entirely at the end of the stator assembly where the one end ring is located.

11. A dynamo-electric machine including a a stack of laminations having a plurality of spaced 6. A dynamo-electric machine including a I stator, comprising a stack of laminations formed with aligned radial circumferentially spaced grooves, end rings having first portions engaging the end laminations and lying inward/ of the grooves and second portions spaced from the stack and projecting radially outwardly farther than the first portions and the stack, bars laid in the grooves and overlying the flrst portions of the end rings and extending radially outwardly as 7 far as the second portions of the rings. and a casing surrounding the stator, end rings, and bars and engaging the bars and second portions of peripheral grooves extending longitudinally of the stack, a pair of end rings abutting opposite ends of the stack of the laminations, bars disposed in the slots in the stack of laminations without being metallically bonded to the'laminations, means rigidly securing the end rings to the ends of the bars by metallic bonds, and a supporting means connected with one end ring for enabling the stator assembly to be supported through the bars and the end rings entirely at the end of the stator assembly where the one end ring is located.

12. A dynamo-electric machine including a stack of laminations having a plurality of spaced peripheral grooves extending longitudinally of the stack, a pair of end rings abutting opposite ends or the stack of the laminations, bars disposed in the slots in the stack of laminations 'without being metallically bonded to the lamina-= tions, means rigidly securing the end rings to the ends of the bars by metallic bonds, a casing surrounding the stack of laminations, and a supporting means connected with one end ring for enabling the stator assembly to be supported through the bars and the end rings entirely in-. dependently of the casing and entirely at the end of the stator assembly where the one end ring is located.

13. A stator assembly comprising a stack of laminations formed with aligned circumferentially spaced grooves, end rings having first portions engaging the end laminations and lying inward of the grooves and second portions spaced from the stack and projecting radially outwardly farther than the first portions and the stack, bars laid in the grooves and overlying the first portions of the end rings and extending radially outwardly as far as the second portion of one end ring, means rigidly securing the end rings to the bars, a casing surrounding the stack of laminations, the end rings, and bars in spaced'relation to the laminations and the first portions of the end rings and in engagement with the bars and the second portion of the said oneend ring, and supporting means connected with the second portion of the other end ring for enabling the stator assembly to be supported through the bars and the end rings entirely independently of the casing and entirely at the end of the stator assembly where the said other. end ring is lcated. l4; A-stator assembly comprising a stack of V laminations formed with aligned circumferentially spaced grooves, end rings having first portions engaging the end l'aminations and lying inward of the grooves and second portions spaced from the stack and projecting radially outwardly farther than the first portions and the stack, bars laid in the grooves and overlying the first portions of the end rings and extending radially outward ly as far as the second portion ofone end ring,

meansrigidly securing the end rings to the bars, a casing surrounding the stack of laminations,

' the end rings, and bars in spaced relation to the laminations and the first portions of the end rings and in engagement with the bars and the second portion of the said one end ring; the second portion of the other end ring being formed as a flange, a support member having a flange abutting-the flange on the said other end ring, and a channel-shaped ring gripping the flanges for enabling the stator assembly to be supported entirely through the support member and independently of the casing.

15. The stator assembly specified in claim 14, the casing abutting the channel-shaped ring and having openings adjacent the channel-shaped ring for admitting cooling air to the spaces be tween thecasing and the stack of laminations' port connected with the other end ring for err-- asvaesa 16. A dynamorelectric machine comprising a stationary stack of laminations, a pair of end rings abutting opposite ends of the stack, a plurality of bars extending longitudinally of the stack of laminations at the periphery thereof, means rigidly securing the ends of the bars to the rings, a rotor positioned within the stack of laminations, supporting and journalling means for one end of the rotor carried by the end ring adjacent the said one end of the rotor, a support connected with the other end ring for enablin the stationary stack of laminations, bars, end rings, and the said one end of the rotor to be carried through the bars and the end rings entirely at the end where the support is located, and means journalling and supporting the other end of the rotor on the support. p

17. A dynamo-electric machine comprising a stationary steel; of laminations, a pair of end rings abutting opposite ends of the stack, a plurality of bars extending longitudinally of the stack of laminations at the periphery thereof, means rigidly securing the ends of the bars to the rings, one end ring having a first portion abutting the stack of laminations and a second portion spaced from the first portion, a rotor positioned within the stack of laminations, bearing means for one end of the rotor carried by the second portion of the said one end ring, brush means for the rotor positioned between the first and second portions of the said one end ring, a supabling the stationary stack of laminations, bars,

end rings, and the said one end of the rotor to he carried through the bars and the-end rings 1 entirely at the end where the support is locawd,

and means journalling and supporting the other end of the rotor on the support.

18. A dynamo-electric machine including a stack of laminations having a plurality of spaced peripheral grooves extending longitudinally of the stack, a pair of end rings abutting opposite ends idly securing the ends of the bars to the end rings, one end ring having afirst portion abuttingthe steels of laminations and a second por- 4 tion spaced from the first portion; an end hell carried by the second portion of the said one end ring, a rotor positioned within the stationary stack of laminations, means journalling one end of the rotor in the bell, brush means for the rotor positioned between the first and second portions of the'said one end ring, the other end ring having e -flange; a support'having a flange, and a channel-shaped ring gripping the flanges for enabling the machine to. be supported entirely at the end where the support is located.

yeanon w. SHERMAN. EUGENE GONYOU. 

